Explanation:

- Option 1: Lord Wellesley

- Known for his role in expanding British control in India through the Subsidiary Alliance System.

- He was not particularly associated with changes in the medium of instruction or official language policy.

- Option 2: Lord Minto

- Known for the Minto-Morley Reforms of 1909.

- These reforms dealt with constitutional changes rather than language or education policy.

- Option 3: William Bentinck

- ?? Was the Governor-General who institutionalized English as a medium of instruction through Macaulay’s Minute on Education (1835).

- His tenure marked significant education reforms including the promotion of English.

- Option 4: Lord Dalhousie

- Known for his expansionist policies and modernization efforts, like railways and telegraph.

- While he modernized India, he did not play a central role in adopting English as the educational medium or official language.

Correct Answer: Option 3: William Bentinck